Falcon clock buffer patch V2 progress

[exxos]

Any thought on my sdma clock wire?

No idea what you did ? The buffer board was designed to use the original track, but I guess if you ran a seperate wire it wouldn't cause any issues.. but if you have that resistor on the clock line (47R or whatever) then it needs to be removed.

[Steve]

@exxos

This is what I have Chris -

Screen Shot 2020-12-29 at 14.19.27.png

Screen Shot 2020-12-29 at 14.13.56.png

[exxos]

Not really sure what's going on there, but I would suggest you remove all the stuff and basically take it back to stock as thats how the buffer is intended to be fitted. If you have anything else anywhere, it will likely screw things up. Fitting the buffer is still as before anyway.

[Steve]

Not really sure what's going on there, but I would suggest you remove all the stuff and basically take it back to stock as thats how the buffer is intended to be fitted. If you have anything else anywhere, it will likely screw things up. Fitting the buffer is still as before anyway.

Well okay.. I mean I am a little confused because the V3 is supposed to mimic the Phantom clock patch, how can it be designed to mimic the Phantom clock patch if you're not sure what is going on there.. that is the phantom clock patch.. Sorry if this sounds rude honestly.

[exxos]

Well okay.. I mean I am a little confused because the V3 is supposed to mimic the Phantom clock patch, how can it be designed to mimic the Phantom clock patch if you're not sure what is going on there.. that is the phantom clock patch.. Sorry if this sounds rude honestly.

The only difference is the addition of the second buffer chip for the SDMA clock.. I am making the assumption its the total propagation delay though the inverters which is what makes it work. So the current buffer does exactly the same, mimics the delays. In fact IIRC mine actually was a tiny bit slower than the original calculated delay. All those caps / resistors which get bodged on the clock lines I already explained many times. They are also fixed a different way. What I don't get is the images you posted, I'm used to proper schematics.

[Rustynutt]

hehe, think Mikro deciphered those :)

Have 4 of your original buffers unused.
Need to get an order in for some V3 (?)
By the time I hack together a Phantom buffer, like having an extra computer board aside :)

With EmuTOS in ROM, am able to boot with a 50 MHz clock.
What I'm finding is the original Nemesis buffer and 150pf cap mod on the DMA doesn't work (well) as with the Nemesis installed.
Audio is fine, DSP-DMA as well, as always, it's SCSI issues.

Tried another builders patch, doesn't do anything (for accelerated bus). They use 0 Ohm resistors in series, possibly allowing for individuals to fine tune, but didn't bother.

Just a follow up note to what I'd seen you mention about your Falcon not booting with a "crowbar" resistor mod on the DMA.
Found pretty much over a 150pf cap on this machine does the same thing. Thought I'd toasted something.

Once an Exxos patch arrives, going to remake the original trace connections, sans the DMA tying in with the FPU clock. That I'll keep separate.

[exxos]

Yeah there's to many clock patch variations about. I'm trying to make mine a "one size fits all" so people don't have to bother messing about all the time. There ones in my store are the latest boards.

[Rustynutt]

Order in :)

[exxos]

Looking at the files for my buffer patch V3 (not yet produced) , it seems for some reason I added another delay to the "DELAY ON" thing. As it was about two years ago I cannot really remember why :lol: Running a quick simulation it seems I increased the delay by 10ns.

There was a post in the German forum were reporting that the delay on was causing problems. Maybe @kohli79 was involved and can remember ? I cannot remember if this was on a stock machine or not ?

I might have increased the delay further to mimic the gated delay on the Phantom. But by all accounts, the delay is probably not really needed And could be creating problems.

At this point I am unsure if to leave that on the board, the delay and the extra delay :shrug:

[Steve]

Hmm I think if it doesn't add any extra cost to the production but you get three choices: no delay, delay, extra delay. That would be something useful. Just keep the default as what you currently have on the v2 board (delay). Just add in the instruction notes that the delay options are for experienced hardware tweakers. Just my 2cents.